\documentclass{article}
\usepackage{graphicx}
\usepackage{array}
\usepackage{booktabs}

\begin{document}
\begin{tabular}{@{}lllllll@{}}
	\toprule
	    &                                      & \multicolumn{5}{c@{}}{Average MuchLonger Name Goes Here:} \\
	\cmidrule(){3-7}
	a   & \rotatebox{90}{\parbox{2cm}{Was this                                                             \\ Identified by You?}}& C & D & E & F & G\\
	\midrule
	5\% & 12.9\%                               & 7.3281  & 7.2445  & 2.1601  & 4.3438  & 4.2821            \\
	    &                                      & (.4038) & (.5058) & (.9049) & (.9032) & (.8831)           \\
	\bottomrule
\end{tabular}
\end{document}
